Concentration of gold bearing materials



Patented Nov. 2, 1937 UNITED STATES CONCENTRATION OF GOL BEARING j v j MATERIALS 7 1 Stanley Tucker, London,, Eng l and,Qas H Minerals SeparationNorth American Corpor eps'tebej tion, New York, N. Y., a :corporationfof f f Y land No Drawingm Original applicationtJanua -y 24, g V

1935, Serial No. 3,267. Dividedand this anpli- I cation May 22, 1937, Serial No., 144, 314...Infjjj- Great Britain January 30, 1934 *9 Claims." (Ch-209 166) Thisapplication is a division of my co-pending application Serial No. 3267, filed January 24, 1935. f

i The present invention relates to an improved 5 process of extracting gold from oresand like materials by aform of physical concentration depending upon the surface propertiesfof the material under treatment, such for. example as froth flotation, and has for its general object 10 to provide for simplicity in such extraction, as well as for high 'goldrecoveryand high gold assayof concentrate.

In accordance with the invention, the'g'ombearing material in the state of finely-divided particles is formed into a pulp with water both in the presence of a mercurial agent and in the presence of an organic sulphur derivative of carbonic acid. By this combination of sub.- stances, as discovered, the gold particles present in the pulp are somodified at their surfaces that they are made amenable to subsequent concentration depending upon their surface properties.

Instead of the organic sulphur derivative of carbonic acid, a sulphidizing agent has also been found capable of use along with the mercurial agent to produce the stated effect on the gold particles present in the pulp, the use of sulphidizing agents in this manner being separately claimed in the aforementioned application Serial In applying the process in apparatus of. the kind ordinarily employed for froth flotation and in conjunction with usual frothing agents so that the concentrate floats in the form of a froth, it has been found that under suitable conditions an almost complete recovery of gold can be obtained by the process in the form of a high grade concentrate.

The surface-modifying agents may be dispersed among the particles of the gold-bearing material during an agitation or grinding operation, carried out prior to concentration.

The mercurial agent may be metallic mercury 5 or a solution of a salt thereof. Mercuric chloride may be used dissolved in an excess of sodium cyanide, a slight excess being suflicient for the purpose. This solution is believed to result in the formation of a sodium mercuric cyanide, with 50 some free sodium cyanide present.

Alkali xanthates are of course included among the organic sulphur derivatives of carbonic acid which may be employed in the process. As to the sulphidizing agents which have been found 55 useful, they include sulphur, soluble sulphides or an dissolved in'sulp hides or'polysulphides'., 11,.Var'iou's. othe agen v y bepresent when the surface-mo g ts are; acting upon the old particles, sd liminaryagitatmn'pr grin ing operation. The use'inthismannerfof {al alt, such" as stannous chloride (snclffhas be n' found to'reduce the quantity l i i erciiinaliae nt which is required. i0

The following isfa "description of a test which the above-stated prewas made'in'carrying the invention into effect:

,A 500 gramme sample of dream Klerksdorp, South Africafa partlyjoxidiz'ed' gold ore containjing'iron s'ulphide;'was comrninuted so as to pass a screeniliaving 10 meshestothe lineal inch and thereafter made into a 'pulp with 250 cubic centimeters of water, To thispulpmercury inthe jmetallic'statelwas' 'added'at the rate of 1.6 lbs.

'per to fw ie eunq fthe p nwa ground in a :pebble mill for fortyfminute's. After thirty minutes of this' g'rir ding, there'were' added to the-mill 2 lbs. jper ton Jof xanthate, 0451b. per ton of 'Anglo'Persian fuel oil, 0.08 lb. per ton of pine oil, and 0.078 lbgpier ton of blast furnace c'reosoteg' These "z a cl ditiqnal agentswere there foreground with the oreforten minutes, j '1 The resulting material was; about such as would pass a screen having 100 meshes to the lineal inch. It was subjected to froth flotation in a sub-aeration machine with two additions of 0.25. lb. per ton of potassium xanthate. As a result 97.7% of the gold in the ore was obtained in a concentrate which assayed 177.2 dwts. per ton, the original sample of ore assaying 12.29 dwts. per ton.

I claim:

1. A process for the concentration of a goldbearing material consisting in forming a pulp of finely-divided particles of the gold-bearing material with water in the presence of a mercurial agent and an organic sulphur derivative of carbonic acid, so that the surfaces of the goldparticles in the pulp are modified by said mercurial agent and organic sulphur derivative of carbonic acid and said gold particles made amenable to concentration depending upon their surface properties, and concentrating said gold particles from the material by flotation.

2. A process for the concentration'of a goldbearing material consisting in forming a pulp of finely-divided particles of the gold-bearing material with water in the presence of a mercurial agent and an organic sulphur derivative of carbonic acid, so that the surfaces ofthe gold particles in the pulp are modified by said mercurial agent and organic sulphur derivative of carbonic acid and said gold particles made amenable to concentration depending upon their surface properties, and concentrating said gold particles from the material by froth flotation.

3. A process for the concentration of a goldbearing material consisting in the preliminary step of agitating a pulp with water of finely divided particles of the gold-bearing materiali'in the presence of a mercurial agent and an organic sulphur derivative of carbonie acid, so that the surfaces of the gold particles thep'mp are modified by said mercurial agent and organic sulphur derivative of carbonic acid and said gold particles made amenable to concentration-depending upon their surface properties, and-thes'ubse'quent step of concentrating said gold particles from the ma-' terial by flotation.

4. A process for the concentration of a gold- 5 bearing material consisting in the preliminary step of grinding the gold-bearing material with water into a pulp of finely-divided particles in the presence of a mercurial agent and'an organic sulphur derivative of carbonic acid, so that the surfaces of the gold particles in the pulp are modified by said mercurial agent and organic sulphur derivative of carbonic acid and said gold particles made amenable to concentration depending upon their surfacfe'properties, and the subsequent step of. concentrating said gold particles from the material by flotation.

5. A process for the concentration of a goldbearing material consisting informing a pulp of finely-divided particles of the gold-bearing material with water in the presence of metallic mercury and an organic sulphurderivative of carbonic acid, so that the surfaee of the gold particles in the pulp are modified by said mercury and organic sulphur derivative of carbonic acid and said gold particles made amenable to concentration depending upon their surface properties, and concentrating said gold particles from the material by flotation.

6. A process for the concentration of, a goldbearing material consisting in forming a pulp of finely-divided particles of the gold-bearing material with water in the: presence of mercuric chloride and organic sulphur derivative fof carbonic acid'and'said gold particles made amenable to concentration depending upon their surface properties, and concentrating said gold particles from the-material by flotation. U

7. A process for the concentration of. a gold-'- bearing material consisting in forming a pulp of finely-divided particles of the gold-bearing ma-: terial with water in the presence of a mercurial agent and an organic sulphur derivative of car bonic acid, so that the surfaces of the gold particles in the pulp are'modified by said mercurial agent and organic sulphur derivative of carbonic acid and said gold particles made amenable to concentration depending upon their surface properties, said mercurial agent comprising mercuric chloride dissolved in an excess of sodium cyanide, and concentrating said gold particles from the material by flotation. 1 8. A process for the concentration of a goldbearing material consisting jin forming a pulp of finely-divided particles of the goldbearing material with water in the presence of a mercurial agent and an alkali xanthate, so that the surfaces of the gold particles in the pulp are modified by said mercurial agent and alkali xanthate and said gold particles made amenable to concentration depending upon theirsurface properties, and concentrating said gold particles from the material by flotation. V V

9. A process for the concentration of a goldbearing material consisting in forming a pulp of finely-divided particles of the gold-bearing material with water in the presence of a mercurial agent and an organic sulphur derivativeof carbonic acid, so'that the surfacesof. the gold par ticles m the pulp are modified by said mercurial agent and organic sulphur derivative of carbonic acid'and said gold particles made amenable to concentration depending upon their surface properties, said pulp being also formed in the presence of stannous chloride, and concentrating said gold particles from the material by flotation.

STANLEY TUCKER. 

